With rapid development of Internet applications and smart terminals, application of Wireless Local Area Networks (WLAN) has become very common. WLAN have been deployed in many public places, such as a factory, a school, a café, and/or the like. Web access through WLAN has become one of the most important means for a subscriber to access network resources. A subscriber may access the Internet to perform an activity such as online business or entertainment anywhere anytime through various terminal devices such as a mobile phone, a computer, and/or the like. With a constant increasing public demand for Internet access through WLAN anywhere anytime, the government and operators have introduced projects for constructing public WLAN hot spots and hot zones. Wide-range WLAN coverage has been achieved in some cities in areas including business centers, universities and institutes, and the like, which further increases a frequency of a terminal subscriber using the WLAN, such that at the same time a number of online WLAN terminals increases rapidly.
At present, network access by a WLAN subscriber is mainly control in modes including a 802.1X mode and via a Dynamic Host Configuration Protocol (DHCP) subscriber option 60, network authentication, and the like. No such mode considers, in initial design, a scene of simultaneous WLAN access by very large scale subscribers, in which case such access modes share a common defect of failing to sense in time whether an online subscriber loses connection to the network abnormally, i.e., providing no mechanism for keeping a subscriber state alive or up-to-date. A subscriber may often lose connection abnormally for various reasons, without sending a disconnected message to an access control device. For a WLAN hot zone, with a lot of subscribers constantly accessing the WLAN and leaving the WLAN with no announcement to a WLAN device, a network device at a WLAN control layer may have to manage a constantly increasing number of online subscribers, such that the network device at the WLAN control layer, particularly a subscriber authenticating and managing device (i.e., a gateway device) may become loaded gradually, leading to resource waste and a certain security risk.
Use of 802.1X+EAP in WLAN subscriber access has become increasingly common, particularly as a main mode in a WLAN access scene for authentication without subscriber awareness. A subscriber normally may perform access, be authenticated, and acquire addresses of three layers by 802.1X+Extensible Authentication Protocol (EAP)+Dynamic Host Configuration Protocol release 4/Dynamic Host Configuration Protocol release 6 (DHCPv4/DHCPv6), 802.1X+EAP+static Internet Protocol (Static IP)/StateLess Address Auto Configuration (SLAAC). No Keeplive mechanism exists for the access protocol between a subscriber and an authenticating node /gateway device, such that upon a link error or once a subscriber loses connection abnormally, the authenticating node /gateway device cannot detect in time that the subscriber has been disconnected, thereby impacting accuracy of subscriber billing and consuming memory resources of the authenticating node /gateway device. Although the authenticating node /gateway device may detect whether a subscriber loses connection to the network abnormally by subscriber connection detection through supplementary means such as a unicast Address Resolution Protocol (ARP) request or idle subscriber traffic detection, such methods are irrelevant to the access protocol 802.1X, and may require additional protocol enablement, and in general consume more resources, impacting performance of the authenticating node /gateway device.
To sum up, no prior solution exists for issues such as waste of the authenticating node resources, a security risk, and/or a billing error caused by a lot of subscribers leaving a network without sending a disconnected message according to related art.